Endoscopic surgical procedures are routinely performed in order to accomplish various surgical tasks. In an endoscopic surgical procedure, small incisions, called portals, are made in the patient. An endoscope, which is a device that allows medical personnel to view the surgical site, is inserted in one of the portals. Surgical instruments used to perform specific surgical tasks are inserted into other portals. The surgeon views the surgical site through the endoscope to determine how to manipulate the surgical instruments in order to accomplish the surgical procedure. An advantage of performing endoscopic surgery is that, since the portions of the body that are cut open are minimized, the portions of the body that need to heal after surgery are likewise reduced. Moreover, during an endoscopic surgical procedure, only relatively small portions of the patient's internal organs and tissue are exposed to the open environment. This minimal opening of the patient's body lessens the extent to which a patient's organs and tissue are open to infection.
The ability to perform endoscopic surgery is enhanced by the development of powered surgical tools especially designed to perform endoscopic surgical procedures. One such tool, for example, is sold by the Applicant's Assignee under the trademark HUMMER II. This tool is in the form of a cylindrical handpiece designed to be held in the hand of the surgeon. Internal to the handpiece there is a motor. A front end of the handpiece is provided with a coupling assembly for releasably holding a cutting accessory. The types of cutting accessories that are attached to these handpieces include edgers, resectors, planers and burrs. Integral with the motor and coupling assembly is a means for transmitting the rotary power developed by the motor to the cutting accessory.
The handpiece also has a suction conduit. This is because, in an endoscopic surgical procedure, irrigating fluid is introduced into the surgical site. This fluid serves as transport media for removing tissue and debris from the surgical site. In order to remove the irrigating fluid, and the material in the fluid, a suction path is provided through the cutting accessory and the handpiece. A suction pump is connected to the handpiece to provide the suction force needed for drawing the fluid and material away from the surgical site. In order to control the suction flow through the cutting accessory and the handpiece, the handpiece is provided with a manually operated valve. Thus, with a single handpiece, a surgeon both manipulates the cutting accessory and controls the suction of material away from the surgical site.
While current endoscopic surgical tool systems have proven useful, there are some disadvantages associated with their construction. Some of these disadvantages are associated with the coupling assemblies integral with the handpieces. For example, many coupling assemblies are provided with release levers that a surgeon or an assistant pivots to place the coupling assembly in a release state wherein a cutting accessory can be removed from the handpiece. Some coupling assemblies are provided with coupling assemblies that not only must be placed in the release state to remove a cutting accessory, but must also be placed in the release state in order to couple a cutting accessory to the handpiece. Requiring medical personnel to perform this step can add to the overall time it takes to remove and replace cutting accessories.
Moreover, often a coupling assembly comprises numerous components. Providing these components and arranging them together to form a functional coupling assembly adds to the overall cost of providing the handpiece to which the coupling assembly is attached. Another disadvantage associated with providing a coupling assembly that has numerous components is that, as with any system, the more components that are provided increases the possibility that, due to the failure of one component, the whole assembly will malfunction. This is especially true when a system is provided with a large number of moving components.
Also, as discussed in application Ser. No. 10/214,937, the Application from which this application claims priority and which is incorporated herein by reference, recently there has been an interest in providing surgical tool systems that allow data to be inductively transferred between the handpiece and the complementary cutting accessory. This system requires the placement of a coil in the distal end, the front end, of the handpiece so that there can be inductive signal transfer between it and a complementary coil in the adjacent proximal end of the associated cutting accessory. This means that, not only must the front end of the handpiece contain the components forming a coupling assembly, it must also have a space in which a coil can be housed. Given the components that comprise some coupling assemblies, the only way both goals can be accomplished is to increase the overall length of the handpiece. This may require lengthening of the proximal end of the complementary cutting accessory, the end fitted in the handpiece. This handpiece lengthening can increase the overall size and weight of the handpiece. These increases run contrary to one goal of modern surgical tool design. This goal being that, to facilitate ease of use of a surgical tool, its size should be kept as small as possible and its weight as low as possible.